import sys


def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    x = int(readline())
    print("Yes" if x >= 30 else "No")


if __name__ == '__main__':
    solve() import sys sys def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    x = int(readline())
    print("Yes" if x >= 30 else "No") solve readline = sys.stdin.buffer.readline readline sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline mod = 10 ** 9 + 7 mod 10 ** 9 + 7 10 ** 9 10 9 7 x = int(readline()) x int(readline()) int readline() readline print("Yes" if x >= 30 else "No") print "Yes" if x >= 30 else "No" x >= 30 x 30 "Yes" "No" if __name__ == '__main__':
    solve() __name__ == '__main__' __name__ '__main__' solve() solve def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    x = int(readline())
    print("Yes" if x >= 30 else "No") def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    x = int(readline())
    print("Yes" if x >= 30 else "No") solve
import sys


def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    x = int(readline())
    print("Yes" if x >= 30 else "No")


if __name__ == '__main__':
    solve()
